The invention concerns a reinforcement for a concrete wall.
It also concerns the use of said reinforcement in a sacrifice formwork.
Before concrete casting, the embodiment of the cast concrete wall requires delimiting the volume into which the material is to be cast by means of formwork walls.
So as to reinforce the resistance of the walls, concrete irons are housed therein by known means and which, when assembled together, form a reinforcement.
Generally speaking, the technique consists of fixing said reinforcements on site or even outside the site, but there remains the problem of transport which increases the cost as these reinforcements are therefore bulky.
Although the concrete casting technique by means of formwork sheetings is widely used, for some years now the technique of sacrifice filtering formwork appeared on the market.
This technique has the advantage of allowing the excess water to escape from the concrete.
In fact, with a filtering wall, the concrete contained in the formwork no longer behaves as a fluid creating a hydrostatic pressure, which is proportional to the height of the cast concrete above the level in question, and owing to this the forces expanded by said concrete are much weaker.
This makes it possible to use light formworks which can be installed without having to use a lifting gear.
In currently known embodiments, said filtering formwork appears in the form of two walls:
obtained by assembling permeable panels retaining the aggregate and allowing the water to escape, the panels being thus made of expanded metal and,
kept at the required space by tie rods which, when the formwork is in place, extend into planes perpendicular to the formwork surfaces.
So as to allow transport of said sacrifice formworks, the tie rods are joined to the formwork walls by joints so that when one of the formwork walls is moved translation, all the tie rods fold down on a given side.
In reality, the tie rods are associated with stiffeners to which the expanded metal panels are secured.
According to the shape of the tie rods, it is possible to make said tie rods participate in the resistance of the cast wall in particular by creating a hooping effect, but mainly inside a plane perpendicular to the plane in which said tie rod extends.
The aim of the invention is to increase the resistance of the walls.
The invention also aims at improving the performances of said sacrifice formworks of the above mentioned type.
To this effect, the purpose of the invention is to provide a reinforcement for a concrete wall comprising a bearing structure made up of two parallel walls, each formed of braces arranged along two orthogonal directions and said walls being suitably maintained spaced apart by tie rods, this reinforcement being characterised in that:
one of the two parallel walls consists of two mutually independent grates,
one of the two independent grates is associated with the other wall by a first set of tie rods, and
the other grate of said wall is also associated with the other wall by a second set of tie rods independent of those of the first set so that when the grates are moved in the opposite direction and along an axis parallel to the plane of the grates, the spacing between the walls is modified.
It also concerns the use of this reinforcement.